Aquatic EcosystemsAquatic Ecosystems

Chapter 7Chapter 7

Environmental ScienceEnvironmental Science

Freshwater EcosystemsFreshwater Ecosystems

• Lakes and PondsLakes and Ponds• WetlandsWetlands• RiversRivers

• Factors affecting which organisms live in Factors affecting which organisms live in freshwater ecosystemsfreshwater ecosystems– TemperatureTemperature– SunlightSunlight– OxygenOxygen– NutrientsNutrients

Aquatic Ecosystem Aquatic Ecosystem OrganismsOrganisms• PlanktonPlankton

– Organisms that float near the surfaceOrganisms that float near the surface– Two typesTwo types

• Phytoplankton – produce most food for ecosystemPhytoplankton – produce most food for ecosystem• Zooplankton – microscopic animalsZooplankton – microscopic animals

• NektonNekton– Free-swimming organismsFree-swimming organisms– Fish, turtles, whalesFish, turtles, whales

• BenthosBenthos– Bottom-dwelling organismsBottom-dwelling organisms– Mussels, worms, barnaclesMussels, worms, barnacles

• DecomposersDecomposers– Break down dead organismsBreak down dead organisms

Lakes and PondsLakes and Ponds

• Layers of a LakeLayers of a Lake– Littoral zoneLittoral zone

• Top layer near the shoreTop layer near the shore

• Nutrient rich Nutrient rich

• Plants are rooted in mudPlants are rooted in mud

• Plants make energy from photosynthesisPlants make energy from photosynthesis– Depend on sunlightDepend on sunlight

– Benthic zoneBenthic zone• Bottom of the lakeBottom of the lake

• Bacteria lives hereBacteria lives here

• No sunlight reaches this layerNo sunlight reaches this layer

• Dead organisms are consumed by decomposers Dead organisms are consumed by decomposers

Lakes and Ponds, Lakes and Ponds, cont.cont.

• EutrophicationEutrophication– Increase of nutrientsIncrease of nutrients– Occurs when a large amount of plant Occurs when a large amount of plant

growth in a lake or pondgrowth in a lake or pond– Increases amount of bacteria Increases amount of bacteria – Bacteria uses up oxygenBacteria uses up oxygen– Eventually not enough oxygen for Eventually not enough oxygen for

organismsorganisms– Runoff can accelerate eutrophicationRunoff can accelerate eutrophication

•Sewage, fertilizers, animal wastesSewage, fertilizers, animal wastes

Freshwater WetlandsFreshwater Wetlands• Areas of lands covered in water for at Areas of lands covered in water for at

least part of the yearleast part of the year• Two types – marshes and swampsTwo types – marshes and swamps• Environmental FunctionsEnvironmental Functions

– Absorb and remove pollutantsAbsorb and remove pollutants– Control flooding by absorbing extra waterControl flooding by absorbing extra water– Provide homes for wildlifeProvide homes for wildlife– Prevent against erosionPrevent against erosion– Provide recreational areas for fishing, etc.Provide recreational areas for fishing, etc.– Provide breeding grounds for fish and Provide breeding grounds for fish and

shellfishshellfish

MarshesMarshes

• Occur in low, flat landsOccur in low, flat lands

• Have little water movementHave little water movement

• Plants root in sediment under waterPlants root in sediment under water– Reeds, rushes, cattailsReeds, rushes, cattails

• Water birds have adapted to marshesWater birds have adapted to marshes– Heron – spearlike beak to grab fishHeron – spearlike beak to grab fish– Ducks – flat beak to sift through water for fishDucks – flat beak to sift through water for fish

• Kinds of marshes according to salinityKinds of marshes according to salinity– Brackish marshes – slightly salty waterBrackish marshes – slightly salty water– Salt marshes – saltier waterSalt marshes – saltier water

SwampsSwamps

• Flat, poorly drained land near Flat, poorly drained land near streamsstreams

• Types of swampsTypes of swamps– Mangrove swampsMangrove swamps

• In warm climates near the ocean (salt water)In warm climates near the ocean (salt water)

– Freshwater swampsFreshwater swamps• Ideal environment for amphibiansIdeal environment for amphibians

• Swamps attract birds and reptilesSwamps attract birds and reptiles– Wood ducks, alligatorsWood ducks, alligators

Human Impact on WetlandsHuman Impact on Wetlands

• Wetlands were considered wastelands Wetlands were considered wastelands where insects breedwhere insects breed– Humans drained the wetlands for this Humans drained the wetlands for this

reasonreason

• Important roles now recognizedImportant roles now recognized– Purifiers for wastewaterPurifiers for wastewater– Flood preventionFlood prevention– Habitats for wildlifeHabitats for wildlife

• Most states have laws against the Most states have laws against the destruction of wetlandsdestruction of wetlands

RiversRivers

• Many begin from snow melt in Many begin from snow melt in mountainsmountains– Cold, full of oxygen, fast movingCold, full of oxygen, fast moving

• River flows down the mountainRiver flows down the mountain– Becomes wider, warmer, slower, less Becomes wider, warmer, slower, less

oxygenoxygen

• A river changes depending on the A river changes depending on the land and climate it is flowing throughland and climate it is flowing through

Rivers in DangerRivers in Danger

• Industries polluting the waterIndustries polluting the water– Kills organismsKills organisms– Makes fish inedibleMakes fish inedible

• Runoff from landRunoff from land– Puts pesticides in the river and sedimentPuts pesticides in the river and sediment

• DamsDams– Change the ecosystem in and around Change the ecosystem in and around

riverriver

Marine EcosystemsMarine Ecosystems

• Costal WetlandsCostal Wetlands– Areas covered by salt water for all or part Areas covered by salt water for all or part

of the timeof the time– Many fish and wildlife live hereMany fish and wildlife live here– Absorb excess rainAbsorb excess rain

•Helps to avoid flooding problemsHelps to avoid flooding problems

– Filter out pollutants and sedimentsFilter out pollutants and sediments– Are recreational areas for boating, fishing, Are recreational areas for boating, fishing,

etcetc

EstuariesEstuaries

• EstuaryEstuary– Area where fresh water from a river Area where fresh water from a river

mixes with salt water from an oceanmixes with salt water from an ocean– Currents form hereCurrents form here

•Cause mud and nutrients to fall to the Cause mud and nutrients to fall to the bottombottom

•Marsh grasses will begin to grow hereMarsh grasses will begin to grow here

– Constantly receiving fresh nutrientsConstantly receiving fresh nutrients•Makes it a very productive ecosystemMakes it a very productive ecosystem

Plants and Animals of Plants and Animals of EstuariesEstuaries• Rooted plantsRooted plants

– Sunlight can reach the bottom since water is Sunlight can reach the bottom since water is shallowshallow

– Nutrient supply is always highNutrient supply is always high

• Plankton live herePlankton live here• Mammals feed on plankton Mammals feed on plankton

– Dolphins, manatees, sealsDolphins, manatees, seals

• Oysters, clams feed on the plantsOysters, clams feed on the plants• All organisms that live here can tolerate All organisms that live here can tolerate

various levels of salinityvarious levels of salinity

Threats to EstuariesThreats to Estuaries

• Ports are built over estuariesPorts are built over estuaries– Provides easy access to oceansProvides easy access to oceans

• Usually populated areas surround an Usually populated areas surround an estuaryestuary– Waste is dumped in the estuaryWaste is dumped in the estuary– PollutantsPollutants

• SewageSewage

• Industrial waste containing toxic chemicalsIndustrial waste containing toxic chemicals

• Agricultural runoff containing pesticides, fertilizersAgricultural runoff containing pesticides, fertilizers

Salt MarshesSalt Marshes

• Develop in estuaries where rivers deposit Develop in estuaries where rivers deposit their load of mineral-rich mudtheir load of mineral-rich mud

• Clams, fish, aquatic birds live hereClams, fish, aquatic birds live here• Protects young animals when smallProtects young animals when small

– ShrimpShrimp– CrabCrab– FishFish– When older, they migrate to the seaWhen older, they migrate to the sea

• Absorbs pollutantsAbsorbs pollutants• Protect inland areasProtect inland areas

Mangrove SwampsMangrove Swamps

• Located along coastal areas of tropical Located along coastal areas of tropical and subtropical zonesand subtropical zones

• Mangrove trees are the main plantMangrove trees are the main plant

• Protects the coastline from erosionProtects the coastline from erosion

• Reduces damage from stormsReduces damage from storms

• Many animals use as a breeding groundsMany animals use as a breeding grounds

• Sometimes filled with waste and Sometimes filled with waste and destroyeddestroyed

Rocky and Sandy ShoresRocky and Sandy Shores

• Rocky ShoresRocky Shores– Many plants anchor to rocksMany plants anchor to rocks– Many animals live on the rocksMany animals live on the rocks

• AnemonesAnemones• MusselsMussels• SpongesSponges

• Sandy ShoresSandy Shores– Dry out when tide goes outDry out when tide goes out– Tiny organisms live off of planktonTiny organisms live off of plankton– Barrier islandsBarrier islands

• Land that runs parallel to the shoreLand that runs parallel to the shore• Protect the mainland and coastal wetlandsProtect the mainland and coastal wetlands

Coral ReefsCoral Reefs

• Limestone ridges built by tiny coral animals Limestone ridges built by tiny coral animals called polypscalled polyps– They secrete skeletons of limestoneThey secrete skeletons of limestone

• Calcium carbonateCalcium carbonate

• Thousands of plants and animals live hereThousands of plants and animals live here– Most diverse ecosystem on EarthMost diverse ecosystem on Earth

• Live in clear, warm salt water Live in clear, warm salt water • Live in shallow water so sunlight can reachLive in shallow water so sunlight can reach• They are predators that never chase their They are predators that never chase their

preyprey– Stinging tentacles to capture organisms that Stinging tentacles to capture organisms that

float byfloat by

Disappearing Coral ReefsDisappearing Coral Reefs• Corals die if:Corals die if:

– Water becomes too hot or too coldWater becomes too hot or too cold– Fresh water drains into the water near reefFresh water drains into the water near reef– Water is too muddy, polluted or too high in nutrientsWater is too muddy, polluted or too high in nutrients

• Causes of coral reef destructionCauses of coral reef destruction– Oil spillsOil spills– SewageSewage– PesticidesPesticides– Silt runoffSilt runoff– OverfishingOverfishing– Careless diversCareless divers– ShipwrecksShipwrecks– Ships dropping anchorShips dropping anchor– People breaking off piecesPeople breaking off pieces

OceansOceans

• Animals Animals – PhytoplanktonPhytoplankton

• Live where light and nutrients are (shallow water)Live where light and nutrients are (shallow water)• Have flagella to keep them from sinking deeper Have flagella to keep them from sinking deeper

– ZooplanktonZooplankton• Feed on phytoplankton near surfaceFeed on phytoplankton near surface• ExamplesExamples

– JellyfishJellyfish– Tiny shrimpTiny shrimp– Larvae of fish, oysters, lobstersLarvae of fish, oysters, lobsters

– DecomposersDecomposers• Live on bottom of oceanLive on bottom of ocean• Consume dead organismsConsume dead organisms

Threats to the OceansThreats to the Oceans

• PollutionPollution– Industrial wasteIndustrial waste– SewageSewage– Plant nutrients (fertilizers, etc.)Plant nutrients (fertilizers, etc.)

• Overfishing and netsOverfishing and nets– Animals can get tangled in nets and dieAnimals can get tangled in nets and die

Arctic and Antarctic Arctic and Antarctic EcosystemsEcosystems

• North and South PolesNorth and South Poles

• Large population of planktonLarge population of plankton

• Many fish eat the planktonMany fish eat the plankton

• Birds, whales, seals feed on the fishBirds, whales, seals feed on the fish

• Fish and seals feed the polar bearsFish and seals feed the polar bears

• Antarctic is not populated by humansAntarctic is not populated by humans– Mainly used for research purposesMainly used for research purposes

Section 2 AssignmentSection 2 Assignment

• Page 185Page 185

• #1-5#1-5

Chapter 7 ReviewChapter 7 Review

• Pages 187-189Pages 187-189

• #6-18, 20-26, 29, 34-35#6-18, 20-26, 29, 34-35